Rotary piston type pump or motor



Sept. 7, 1965 H. MOSBACHER ROTARY PISTON TYPE PUMP OR MOTOR 2 Sheets-Sheet 1 Filed Oct. 31, 1962 Sept. 7, 1965 B. H. MOSBACHER ROTARY PISTON TYPE PUMP OR MOTOR 2 Sheets-Sheet 2 Filed Oct. 31, 1962 United States Patent 3,204,571 ROTARY PISTON TYPE PUMP 0R MOTOR Bruce H. Mosbacher, Rockford, Ill., assignor to Roper Hydraulics, lnc., Commerce, Ga., a corporation of Georgia Filed Oct. 31, 1962, Ser. No. 234,385 4 Claims. ((11. 103174) This invention relates to a piston type pump or motor device.

The present invention is directed to a pump or motor device including a pump casing, a cylinder member in the casing defining a pump displacement chamber, and a piston member reciprocable in the displacement chamber. An eccentric drive is connected to one of the members for moving it in an orbital path to effect relative reciprocation of the piston and cylinder members and thereby cyclically vary the volume of the displacement chamber. The cylinder member has a valve port communicating with the displacement chamber and cooperating with inlet and discharge ports of the pump casing to communicate the displacement chamber with the inlet and discharge ports as the cylinder member moves relative to the casing.

An important object of this invention is to provide a pump or motor device of the type described having an improved valve and passage arrangement for controlling the flow of fluid to and from the displacement chamber in proper timed relation with the movement of the piston member in the displacement chamber.

Another object of this invention is to provide a pump or motor device of the type described and which effects relatively rapid movement of the valve port in the cylinder member between the inlet and discharge ports in the pump casing when the piston and cylinder member are mounting the piston and cylinder members to avoid application of lateral loads to the piston and cylinder members during relative reciprocation of the same.

Still another object of this invention is to provide a pump or motor device which is of simple and economical construction and which is reliable and efiicient in operation.

These, together with other objects and advantages of I this invention will be more readily appreciated as the same becomes understood by reference to the following detailed description when taken in connection with the accompanying drawings wherein:

FIG. 1 is a longitudinal sectional view through the pump or motor;

FIG. 2 is a transverse sectional view taken on the plane 22 of FIG. 1;

FIG. 3 is a transverse sectional view taken on the plane 3-3 of FIG. 1;

FIG. 4 is a fragmentary sectional view taken on the r plane 44 of FIG. 2;

FIG. 5 is a schematic view diagrammatically and graphically illustrating the movement of the cylinder and valve port;

FIG. 6 is a longitudinal sectional view through a modified form of pump apparatus; and

FIG. 7 is a transverse sectional view taken on the plane 1 7-7 of FIG. 6.

The present invention is directed to a radial piston type I pumping apparatus and, in general, includes a casing 10, a plurality of pistons 11, cylinder means 12, and a drive means including a shaft 13 having an eccentric 14. In accordance with the present invention, the pistons and cylinders are operatively interconnected to each other and to the eccentric means so that the pistons and cylinders are cyclically reciprocated in a direction generally radially of the shaft to vary the volume of the displacement chambers in the cylinders and the cylinders are oscillated in a direction circumferentially of the shaft to effect valving of the displacement chambers in timed relation with the reciprocation.

In the embodiment shown herein, the casing 10 includes an annular portion 21 having an integral end wall 22 at one side and a removable end wall 23 at the other side. As best shown in FIG. 1, the removable end wall 23 has a stepped peripheral wall 24 which is sealed to the annular portion 21 as by an O-ring 25. The removable end wall 23 is clamped in position on the casing as by fasteners 26 that extend through openings 27 in the end wall 22 and are threaded into the removable end wall 23 as is clearly shown in FIG. 1. The heads of the fasteners 26 are conveniently sealed to the casing as by O-rings 29.

The shaft 13 is rotatably supported in a bearing member 31 mounted on the end member 23 and clamped in position by a clamp ring 32 and fasteners 33. An O-ring 34 is provided for sealing the bearing 31 to the end member 23. The outer face 35 of the bearing member is conveniently arranged to form a stationary shaft seal member which cooperates with a rotary seal member 36 carried by the shaft. The rotary seal member has an end face 37 disposed in running engagement with the stationary seal face 35 and yieldably urged thereagainst by a spring-means 38. The spring means is advantageously in the form of a series of axially stacked wavy washers which are not affected by centrifugal force encountered during rotation of the shaft. An O-ring 39 is provided for sealing the rotary seal member to the shaft and, as will be noted from FIG. 1, the outer periphery of the O- ring 39 engages the rotary seal member at a point intermediate the radially inner and outer edges of the seal face 37 to provide substantial hydraulic balance on the rotary seal member. The shaft 13 also has a trunnion 41 extending axially thereof and rotatably supported in a bearing 42 on the end wall 22 of the casing. Obviously, the trunnion 41 could be used to drive a boost pump (not shown) if it is desired to increase the inlet pressure supplied to the pump 10.

The end wall 22 and end member 23 have faces 45 and 46 which are spaced apart to define a pump cavity therebetween and the cylinder means are disposed in the pump cavity. In the embodiments illustrated, the cylinder means 12 includes a plurality of independent cylinder members having fiat end faces 47 and 48 disposed in running engagement with the Wall faces 45 and 46, respectively. As shown herein, the end faces 45 and 46 of the end Walls are conveniently maintained in proper spaced relation by arcuate blocks 49 disposed between the end faces 45 and 46 and maintained in assembled relation by the fasteners 26. The cylinder members 12 are formed with a thickness slightly less than the thickness of the blocks 49 so as to permit free sliding movement of the cylinder members between the end faces 45 and 46.

The cylinders 12 each have bores 54 therein which slidably receive the piston members 11 to form displacement chambers 55 in the cylinders. The pistons and cylinders form pumping units which are connected to the eccentric 14 and to the casing in such a manner that the pistons extend generally radially of the shaft tocyclically vary the volume of the displacement chambers in response to the radial shifting movement produced by the eccentric.

In the preferred embodiments illustrated in the drawings, the cylinder members 12 are individually connected to the eccentric 14 for movement thereby in an orbital path, and the piston members 11 are swingably mounted as by pins on the casing. As best shown in FIGS. 2 and 3, the cylinder members are formed with ears designated 57a-57c on their radially inner ends which are rotatably supported on a bearing 53 on the eccentric. The ears 57a-57c on the several cylinder members are axially offset from each other and overlap as shown in FIG. 1.

As the shaft 13 rotates and drives the eccentric 14, the cylinder members are radially shifted relative to the piston members to cyclically vary the volume of the displacement chambers 55 in the cylinder members. The pumping units formed by the cylinder members and piston members are constrained against rotation with the shaft by the pivot pins 56. However, the piston and cylinder members do oscillate in a direction circumferentially of the shaft as the eccentric rotates. In accordance with the present invention, this oscillatory movement of the cylinder members, which is in a direction circumferentially of the shaft and crosswise of the axis of the piston members, is utilized to achieve valving of the displacement chambers in proper timed relation with the reciprocation of the pistons and cylinders.

For this purpose, each of the cylinder members is formed with a valve port designated 61 that communicates with the displacement chamber 54 and with at least one side face 47 of the cylinder member. Advantageously, the valve port 61 extends completely through the cylinder member as best shown in FIG. 4 to more nearly equalize the pressures at opposite sides of the cylinder member for axial hydraulic balance. A plurality of inlet and discharge ports 62 and 63, each individual to one of the cylinder members, are formed in the end face 47 of the casing and are circumferentially spaced apart, as is best shown in FIG. 3. The valve port 51 in the cylinder member is movable in a direction circumferentially of the shaft and crosswise of the axis of the piston member, alternately into communication with the inlet and discharge ports. As will be seen from FIG. 5, the valve port 61 not only oscillates in a direction circumferentially of the shaft, but also moves radially with the piston member as the eccentric is rotated. The valve port 61 is advantageously elongated in a direction parallel to the axis of the cylinder member and the inlet and discharge ports 62 and 63 are spaced apart a distance at least equal to, and preferably greater than, the circumferential width of the valve port 61 so that flow between one of the ports such as 62 and the valve port 61 is completely terminated before the valve port moves into registry with the other port 63. As is clearly shown in FIG. 5, the inlet and discharge ports 62 and 63 are spaced radially from the shaft a distance corresponding to the radial spacing of the valve port 61 from the center of the shaft 13.

Any suitable arrangement may be provided for communicating the inlet and discharge ports with the supply and return conduits and, if desired, the inlet and discharge ports can be connected to separate supply and return conduits to provide a plurality of separate pumps within a single casing or, alternatively, the several inlet and discharge ports can be interconnected to provide a common inlet and discharge. In the form shown, a common inlet '71 is provided in the casing and communicates through an opening 72 with the interior of the casing. Each of the inlet ports 62 are advantageously formed with enlarged portions 73 that extend beyond the sides of the cylinder members and communicate with the interior of the casing alongside the cylinder members. Thus, the fluid flows from the inlet passage 71 and port 72 through the pump cavity to the several inlet ports 62. An outlet passage 80 is also provided on the casing and, as best shown in FIG. 3, bores 74 and '75 are formed in the end Wall 22 of the casing and communicate through lateral bores 76 with the several outlet ports 63. In the embodiment illustrated, three pumping units are provided and are angularly spaced apart 120 about the shaft so that the pumping units are each 120 out of phase with each other. The outputs of the several pumping units thus combine to provide a relatively smooth flow from the pump. Conversely, if the unit is operated as a motor, the several pumping units will combine to provide smooth power output. In order to aid in equalizing the pressures on opposite sides of the cylinder members, a second passage 70 is advantageously provided in each cylinder member. As best shown in FIGS. 2 and 4, the passage 70 opens at opposite sides of the cylinder member and is spaced in a direction crosswise of the axis of the cylinder 54 from the valve port 61, to apply pressure from the discharge port 63 to the relatively opposite side of the cylinder member, when the valve port 61 is in communication with the inlet port 62, to thereby provide substantial axial hydraulic balance on the cylinder members.

A modified form of pump or motor is illustrated in FIGS. 6 and 7. In this embodiment, a casing 10, a piston member 11, shaft 13 and eccentric 14 are constructed and arranged in the same manner as previously described, and like numerals are used to designate corresponding parts. A modified form of cylinder construction is provided and like numerals followed by the subscript are used to designate the modified parts. As in the preceding embodiment, the cylinder 12 has a bore 54' which slidably receives the piston 11 and opposed side faces 47' and 48' disposed in rubbing engagement with the side Walls 45 and 46 of the casing. Valve ports 61 are provided in each of the cylinder members for movement therewith alternately into communication with the inlet and discharge ports in the casing, and a pressure equalizing passage 70' is also provided in each cylinder member to equalize the pressures at opposite sides thereof, when the valve port 61 is in communication with the inlet. In this embodiment, each of the cylinder members 12 is formed with an arcuate inner end 57 which is adapted to engage the eccentric 14 on the shaft. The cylinder members are supported on the eccentric portion for limited angular movement relative to each other by means of rings 80' disposed concentric with the eccentric portion 14 and which extend into grooves 81' in opposite sides of the cylinder members. Thus, the rings retain the cylinder members in assembled relation on the eccentric portion and permit the limited relative angular movement necessary for orbital movement of the eccentric portion. While the cylinder members can be formed in any desired manner, the cylinder members are advantageously formed as a unit which is bored to form the arcuate portions 57'; counterbored to form the grooves 81' concentric with the portions 57', and the sides 47' and 48' ground and finished while the cylinder members are part of a unitary assembly, to provide uniform thickness. The cylinder members can then be cut apart along the lines indicated at 82 to separate the cylinder members from each other. The width of the cut between the cylinder members is made sufficient to allow the aforementioned limited relative movement between the cylinder members during rotation of the eccentric.

From the foregoing it is thought that the operation and construction of the device will be readily understood. The device can be operated as either a pump or motor. During rotation of the shaft, the cylinder members are shifted radially of the shaft to cyclically vary the volume of the displacement chambers 55. The radial shifting movement of the cylinder is indicated in FIG. 5 by the generally sinusoidal curve designated T. Simultaneously, the movement of the eccentric 14 produces a circumferential shifting of the cylinder member in a direction crosswise of the axis of the cylinder. This circumferential shifting of the cylinder member is substantially out of phase with the radial shifting of the cylinder member, and is indicated by the generally sinusoidal curve designated V in FIG. 5. Thus, by utilizing the radial shifting movement of the cylinders to produce the pumping action and the circumferential shifting of the cylinders to provide the valving action, valving of the cylinders in proper timed relation with the reciprocation of the pistons is achieved with the valve ports located alongside the respective cylinders. In addition, it will be noted that the circumferential shifting movement of the cylinder is most rapid at the time the cylinder port 61 moves out of communication with one of the ports such as 62 and into communication with the other of the ports such as 63. This rapid shifting movement of the cylinder port between the inlet and outlet ports occurs at the time the piston is at the top and bottom dead center, and consequently has its slowest rate of movement. This, in turn, permits use of a slight overlap in the valving, viz. the width of the valve port 61 can be made slightly less than the land between the inlet and outlet ports, as shown in FIG. 5, so as to provide more positive shut off and minimize leakage of fiuid between the inlet and outlet ports during shifting of the valve port.

I claim:

1. A radial piston type pump or motor comprising, a pump casing defining a cavity, a shaft extending into said casing and having eccentric means thereon, a plurality of pumping units each including an individual cylinder member defining a displacement chamber and a piston member slidable in said displacement chamber, means pivotally connecting said piston members to said casing at fixed points angularly spaced around the axis of said shaft for oscillatory movement about axes fixed on the respective piston members and paralleling said shaft, means mounting said individual cylinder members on said eccentric means for movement by said eccentric means in an orbital path and for limited relative angular shifting movement between the several cylinder members, said eccentric means cyclically reciprocating said cylinder member in a direction generally radially of said shaft to vary the volume of said displacement chambers and also cyclically oscillating each unit in a direction circumferentially of the shaft and crosswise of the axis of said piston members, said casing including end wall means having a plurality of inlet and discharge ports therein arranged in pairs individual to each unit and angularly spaced apart about the axis of said shaft, said cylinder members having a face slidably abutting said end wall means of the casing and a valve port in each cylinder member communicating with the displacement chamber therein and movable with the cylinder in a direction circumferentially of said shaft alternately into communication with respective ones of said inlet and discharge ports.

2. A radial piston type pump or motor comprising, a pump casing defining a cavity, a shaft extending into said casing and having eccentric means thereon, a plurality of pumping units each including an individual cylinder member defining a displacement chamber and a piston member slidable in said displacement chamber, means pivotally connecting said piston members to said casing at fixed points angularly spaced around the axis of said shaft for oscillatory movement about axes fixed on the respective piston members and paralleling said shaft, means mounting said individual cylinder members on said eccentric means for movement by said eccentric means in an orbital path and for limited relative angular shifting movement between the several cylinder members, said eccentric means cyclically reciprocating said cylinder member in a direction generally radially of said shaft to vary the volume of said displacement chamhers and also cyclically oscillating each unit in a direction circumferentially of the shaft and crosswise of the axis of said piston members, said casing including first and second end wall means axially spaced apart a distance to slidably receive said cylinder members there-between, said end wall means having a plurality of inlet and discharge ports therein arranged in pairs individual to each unit and angularly spaced apart about the axis of said shaft, said cylinder members having first and second faces slidably abutting said first and second end wall means, one of said faces of each cylinder member having a valve port therein communicating with the displacement chamber therein and movable with the cylinder member in a direction circumferentially of said shaft alternately into communication with respective ones of said inlet and discharge ports.

3. A radial piston type pump or motor comprising, a pump casing defining a cavity, a shaft extending into said casing and having eccentric means thereon, a plurality of pumping units each including an individual cylinder member defining a displacement chamber and a piston member slidable in said displacement chamber, means pivotally connecting said piston membersto said casing at fixed points angularly spaced around the axis of said shaft for oscillatory movement about axes fixed on the respective piston members and paralleling said shaft, means mounting said individual cylinder members on said eccentric means for movement by said eccentric means in an orbital path and for limited relative angular shifting movement between the several cylinder members, said eccentric means cyclically reciprocating said cylinder member in a direction generally radially of said shaft to vary the volume of said displacement chambers and also cyclically oscillating each unit in a direction circumferentially of the shaft and crosswise of the axis of said piston members, said casing including first and second end wall means axially spaced apart a distance to slidably receive said cylinder members therebetween, said end wall means having a plurality of inlet and discharge ports therein arranged in pairs individual to each unit and angularly spaced apart about the axis of said shaft, said cylinder members having first and second faces slidably abutting said first and second end wall means, each cylinder member having a valve passage communicating with the displacement chamber therein and opening at each said first and second faces of the cylinder member, said valve passage being movable with the cylinder member in a direction circumferentially of said shaft alternately into communication with respective ones of said inlet and discharge ports.

4. A radial piston type pump or motor comprising, a pump casing defining a cavity, a shaft extending into said casing and having eccentric means thereon, a plurality of pumping units each including an individual cylinder member defining a displacement chamber and a piston member slidable in said displacement chamber, means pivotally connecting said piston members to said casing at fixed points angularly spaced around the axis of said shaft for oscillatory movement about axes fixed on the respective piston members and paralleling said shaft, means mounting said individual cylinder members on said eccentric means for movement by said eccentric means in an orbital path and for limited relative angular shifting movement between the several cylinder members, said eccentric means cyclically reciprocating said cylinder members in a direction generally radially of said shaft to vary the volume of said displacement chambers and also cyclically oscillating each unit in a direction circumferentially of the shaft and crosswise of the axis of said piston members, said casing including first and second end wall means axially spaced apart a distance to slidably receive said cylinder members therebetween, said end wall means having a plurality of inlet and discharge ports therein arranged in pairs individual to each unit and angularly spaced apart about the axis of said shaft, said cylinder members having first and second faces slidably abutting said first and second end Wall means, each cylinder member having a valve passage communicating 7 8 With the displacement chamber therein and opening at References Cited by the Examiner each said first and second faces of the cylinder member, UNITED STATES PATENTS said valve passage being movable with the cylinder memher in a direction circumferentially of said shaft alter- 640,039 12/99 Smlth 12164 nately into communication with respective ones of said 5 1,940,957 12/33 Larsh 103159 inlet and discharge ports, each cylinder member having a FOREIGN PATENTS pressure balancing passage sealed from said displacement 1,094,198 12/60 Germanychamber and opening at each said first and second faces of the cylinder member, said pressure balancing passage being located to communicate with said discharge port 10 LAURENCE EFNER Primary Examiner.

when said valve passage communicates with said inlet port JOSEPH H. BRANSON, JR., Examzner.

321,313 11/29 Great Britain. 

1. A RADIAL PISTON TYPE PUMP OR MOTOR COMPRISING, A PUMP CASING DEFINING A CAVITY, A SHAFT EXTENDING INTO SAID CASING AND HAVING ECCENTRIC MEANS THEREON, A PLURALITY OF PUMPING UNITS EACH INCLUDING AN INDIVIDUAL CYLINDER MEMBER DEFINING A DISPLACEMENT CHAMBER AND A PISTON MEMBER SLIDABLE IN SAID DISPLACEMENT CHAMBER, MEANS PIVOTALLY CONNECTING SAID PISTON MEMBES TO SAID CASING AT FIXED POINTS ANGULARLY SPACED AROND THE AXIS OF SAID SHAFTS FOR OSCILLATORY MOVEMENT ABOUT AXES FIXED ON THE RESPECTIVE PISTON MEMBERS AND PARALLELING SAID SHAFT, MEANS MOUNTING SAID INDIVIDUAL CYLINDER MEMBERS ON SAID ECCENTRIC MEANS FOR MOVEMENT BY SAID ECCENTRIC MEANS IN AN ORBITAL PATH AND FOR LIMITED RELATIVE ANGULAR SHIFTING MOVEMENT BETWEEN THE SEVERAL CYLINDER MEMBERS, SAID ECCENTRIC MEANS CYCLICALLY RECIPROCATIING SAID CYLINDER MEMBER IN A DIRECTION GENERALLY RADIALLY OF SAID SHAFT TO VARY THE VOLUME OF SAID DISPLACEMENT CHAMBERS AND ALSO CYCLICALLY OSCILLATING EACH UNIT IN A DIRECTION CIRCUMFERENTIALLY OF THE SHAFT AND CROSSWISE OF THE AXIS OF SAID PISTON MEMBERS, SAID CASING INCLUDING END WALL MENS HAVING A PLURALITY OF INLET AND DISCHARGE PORTS THEREIN ARRANGED IN PAIRS INDIVIDUAL TO EACH UNIT AND ANGULARLY SPACED APART ABOUT THE AXIS OF SAID SHAFT, SAID CYLINDER MEMBERS HAVING A FACE SLIDABLE ABUTTING SAID END WALL MEANS OF THE CASING AND A VALVE PORT IN EACH CYLINDER MEMBER COMMUNICATING WITH THE DISPLACEMENT CHAMBER THEREIN AND MOVABLE WITH THE CYLINDER IN A DIRECTION CIRCUMFERENTIALLY OF SAID SHAFT ALTERNATELY INTO COMMUNICATION WITH RESPECTIVE ONES OF SAID INLET AND DISCHARGE PORTS. 